The research program proposed investigates various aspects of visual behavior in human infants in the first half year of life. Experiments proposed include studies of the physical characteristics of visual stimuli which influence visual behavior, of the development of peripheral vision, of the development of form perception and of the development of early social response. The long term goal of these studies is an understanding of how the infant develops and uses a stable and reliable cognitive model of his world. The technique used, infared corneal reflection photography, allows a detailed record of where on a visual stimulus an infant fixates during scanning. Eye movement data would be supplemented by data on heart rate changes, pupil diameter changes and, in some cases, sucking. The research would be significant in a number of ways. First, it would yield data on the dimensions in the environment which are the basis of infant visual response. Second, it would allow study of how the infant organizes his perceptions into higher order structures. Third, it would relate to the visual mechanisms mediating social development in early infancy. Fourth, such data may provide the basis for a new tool for the assessment of intellectual-developmental functioning in infancy. Fifth, the research would relate to, and perhaps clarify, existing data on the eye movements of older children and adults. Finally, such data are of great importance theoretically, since they relate to a period which is critical for the issue of whether perception is learned or innate.